Probing compositional engineering effects on lead-free perovskiteinspired nanocrystal thin films using correlative nonlinear optical microscopy

We introduce the use of correlative third-harmonic generation and multiphoton-induced luminescence microscopy to investigate the impact of manganese (Mn) doping to bismuth (Bi)-based perovskite-inspired nanocrystal thin films. The technique was found to be extremely sensitive to the microscopic features of the perovskite film and its structural compositions, allowing the unambiguous detection of compositionally different emitters in the perovskite film and manipulation of their nonlinear optical responses. Our work unveils a new way to investigate, manipulate, and exploit perovskite-inspired functional materials for nonlinear optical conversion at the nanoscale.